A type of metabolic engineering described in this proposal, and referred to as "industrial" metabolic engineering, is a method for performing strain improvement in industrial microorganisms by harnessing the power of in vitro transposition mutagenesis. The industrial microorganisms of interest to this study are the actinomycetes, a group of soil bacteria that are best known for their ability to produce over two thirds of the worlds naturally derived antibiotics, anticancer agents, and immunosuppressants currently in medical use. Industrial metabolic engineering also benefits from technical progress made in microfermentation screening. Microfermentations make possible the economical screening of large numbers of mutants in order find improved strains. Because of the transposon tagging process, these improved mutants can be easily reverse engineered to reveal the identity of the strain improvement mutation they harbor in their genome. Once the strain improvement target is identified, new genetic and metabolic knowledge is revealed that can lead to further optimization of the technology and extension of the technology to other industrial fermentation processes of medical importance. The model organism used in this study is the erythromycin producing organism, S. erythraea, that has been the subject of over 50 years of intensive genetic and biochemical research, providing a solid foundation upon which to build the fundamentals for the emerging field of predictive metabolic engineering of industrial microorganisms. 1 PROJECTNARRATIVE Industrial Metabolic Engineering Metabolic engineering will someday give scientists the ability to predicatively manipulate biological organisms for many useful purposes ranging from strain improvement and other industrial biotech applications, to allowing greater agricultural production, permitting more efficient and safer energy production, and providing better understanding of the metabolic basis for medical conditions that will assist in the development of new cures. For some promising new natural products, our technology could make the difference between a drug making it to market, or being abandoned due to inadequate supply of the drug for testing or commercial distribution. [unreadable] [unreadable] [unreadable]